The objective of this research is to determine the effect of the structure of a fiber preform on its conformability to certain part shapes -- e.g., corners, curves. The use of fiber preforms can significantly open up the medium to high volume composite markets due to its potential to produce cost-effective yet structurally sound, near net shape parts. However, complex part shapes can result in regions where the alignment of fibers is not in the direction of maximum loading. In addition, fiber movement can result in regions of low fiber volume fraction leading to weak spots. Both of these variations tend to occur in areas where stress concentrations are also a concern, resulting in failures below projected loading capacity. The project will investigate several methods of measuring preform deformation (e.g., tensile, shear, and bending behavior) -- including the use of optical and image analysis techniques, tracer fibers, and various load configurations simulating processing conditions. It is expected that this preliminary work will lead to a more detailed study resulting in the quantification of the deformation response of aligned, biaxial, and random fiber mats. By understanding the deformation behavior of different fiber mat geometries, the response of various preform architectures to processing conditions can be predicted and thus optimized to fit the desired part shape. A detailed understanding of the behavior of fiber mats is essential to the widespread use of composite materials in the "mass market" application areas, particularly in the automotive industry.
